Nightmare though it may be for MLS coaches, the Concacaf Gold Cup is a rich vein of opportunity for players and fans.

Dozens of players must pick up the slack to cover for their teammates called away for international duty, but it's not just the direct replacements who are compelled to measure up. Collective effort can be just as critical as individual performance.

So for this weekend's games here are five unheralded players who fans and observers should watch as their teams compensate for significant losses.

Matt Besler (Kansas City) - The rookie has been playing outside back though his MLS future will probably be as a central defender. Rauwshan McKenzie is replacing Jimmy Conrad in the middle and as his name implies, he's a bit raw. So is Besler, yet how they handle Brian Mullan and the other Dynamo attackers who came their way will determine what the Wizards get out of this important home match.

Ned Grabavoy (Real Salt Lake) -Will Johnson is with Canada, Kyle Beckerman is with the USA, and Javier Morales is limping, so this ex-Quake midfielder will be handed a big test against his former team in a vital home game. San Jose's midfield is hardly stellar but it can function well as a unit, so Grabavoy's ability to hang tough in the middle and support his attacking teammates is a key element.

Nick LaBrocca (Colorado) - He might well line up on the left side as the direct replacement for Colin Clark, but that spot could be filled by Jacob Peterson or Mehdi Ballouchy. His slick ball skills and pace can also spark an attack missing Omar Cummings, so he may take advantage of a Fire midfield lacking Logan Pause as the Rapids host a team that mirrors its 5-3-6 record.

Eric Brunner (Columbus) - Rather quietly he's tackled strongly and sharply alongside Chad Marshall in the middle of the Crew's defense, so whether he's paired with Danny O'Rourke or somebody else for a home match with D.C. United, his team will need the poise and experience he's gained over the past two months to get a victory that would move it atop the Eastern Conference.

Brek Shea (FC Dallas) - Attacking by committee is the best way to make up for the absence of Kenny Cooper, yet this tall (6-foot-3) teenager has already proven to MLS defenses that he can be a handful. Cooper has scored "only" seven of FCD's paltry total of 18 goals, thus others need to get it done as well, so if the U.S. under-20 international is working the box, tussling with defenders and winning stuff in the air, FCD should get scoring chances against the New York Red Bulls, the league's worst road team (0-9-1).